Our major research interest is the control of cell division in E. coli. We have focused on a cluster of cell division genes, ftsQ, ftsA and ftsZ, that are located at 2 min in the genetic map. One of these genes, ftsZ, is responsible for coupling DNA replication to cell division, and may control the frequency of septum formation. We have found that sulB mutations, which uncouple DNA replication from cell division, map in ftsZ. Further analysis of these and similar mutations should reveal the mechanism by which cell division is inhibited and lead to the lucidation of the key role the ftsZ gene plays in the cell division pathway. The regulation of the fts genes is being explored. First, the DNA sequence of these genes is being determined. Examination of the sequence is revealing gene location and potential promoters and will be further analyzed for potential regulatory features. Second, SI mapping, in vitro trasnscription and Northern blots will be done to elucidate transcriptional features. Third, 4 restriction fragments have been found to contain promoter activity when analyzed through the construction of galk operon fusions. These fusions will be utilized to analyze the regulation of these promoters and isolate regulatory mutants. The function of the ftsZ gene will be analyzed through the use of in frame gene fusions between lacZ and ftsZ. One fusion product inhibits cell division and appears to be an analogue of the cell division inhibitor sulA. Analysis of resistant mutants should elucidate the inhibition mechanism and define proteins that interact with ftsZ. A second fusion is a high molecular weight protein and will be used to obtain antibodies to ftsZ. These antibodies will be used to monitor the ftsZ protein in vivo.